Dear Maintainer,

When transferring files from a machine with rsync-3.2.3-4 to a machine with
rsync-3.2.3-8, several transfers fail with:

    ERROR: $filename failed verification -- update discarded.

In a transfer of a large directory, approximately 20% of files failed to copy.

Which files succeed and which files fail seems to be reproducible between runs,
so I do not suspect hardware issues. I ran the command on the machine with -4,
and it failed whether sending or receiving. Below is the --debug=all output
for a failed (receiving) run of a single small file:

    (Client) Protocol versions: remote=31, negotiated=31
    Client negotiated checksum: xxh128
    get_local_name count=1 /tmp/
    [Receiver] change_dir(/tmp)
    generator starting pid=19947
    delta-transmission enabled
    recv_generator(numbers.mli,0)
    generate_files phase=1
    recv_files(1) starting
    recv_files(numbers.mli)
    [receiver] send_msg_int(9, 0)
    recv_files phase=1
    recv_generator(numbers.mli,0)
    generate_files phase=2
    recv_files(numbers.mli)
    ERROR: numbers.mli failed verification -- update discarded.
    recv_files phase=2
    recv_files finished
    [receiver] send_msg(10, 8)
    generate_files phase=3
    generate_files finished
    client_run2 waiting on 19948
    rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1816) [generator=3.2.3]
    [generator] _exit_cleanup(code=23, file=main.c, line=1816): about to call exit(23)

The file in question is available at:

https://gist.githubusercontent.com/stedolan/167ecb4b7e4ca7c8efb815c20173f45b/raw/a2d17391fe394ae6f23b7879cfb845ee6d152c2e/numbers.mli

The problem went away when both sides were upgraded to rsync-3.2.3-8, so perhaps
some protocol incompatibility was introduced between these versions without
changing the protocol version number.

Hello Stephen,

not matter that the ticket is quit old the versions you mentioned are
also outdated, I think this is a serious matter that should be looked
into. But I am not the Debian maintainer how packaged that.

Did you ever observed that behavior with future version of rsync?

I checked the debian changelog for rsync. IMHO to many things happend
between this two Debian-intern versions. Many patches, etc. Most of the
changelog entries are useless for outsiders and hard to understand for
someone outside of the rsync world.
If there is no feedback from Samual (the DM for this package) I would
suggest we close the ticket because the versions you mentioned are not
relevant anymore and also no one else reported an issue like this.

Regards,
Christian